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/* Copyright (C) 1994-2003 Revolution Software Ltd
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* $Header$
*/
//------------------------------------------------------------------------------------
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
//#include "src\driver96.h"
#include "build_display.h"
#include "debug.h"
#include "defs.h"
#include "header.h"
#include "interpreter.h"
#include "layers.h"
#include "memory.h"
#include "object.h"
#include "protocol.h"
#include "resman.h"
#include "scroll.h"
//------------------------------------------------------------------------------------
#define MAX_SCROLL_DISTANCE 8 // max no of pixel allowed to scroll per cycle
//------------------------------------------------------------------------------------
uint8 scroll_fraction=16; // used to be a define, but now it's flexible (see new functions below)
//------------------------------------------------------------------------------------
void Set_scrolling(void) //S2.1(2Mar94jel) refurnished Tony25Sept96 :-)
{
// feet_x = 128+320 // normally we aim to get George's feet at (320,250) from top left of screen window
// feet_y = 128+250
// set scroll offsets according to the player's coords
int16 offset_x;
int16 offset_y;
int16 dx, dy;
uint16 scroll_distance_x; // how much we want to scroll
uint16 scroll_distance_y;
if (SCROLL_X || SCROLL_Y) // if the scroll offsets are being forced in script (05feb97 JAMES)
{
// ensure not too far right
if (SCROLL_X < this_screen.max_scroll_offset_x)
this_screen.scroll_offset_x = SCROLL_X;
else
this_screen.scroll_offset_x = this_screen.max_scroll_offset_x;
// ensure not too far down
if (SCROLL_Y < this_screen.max_scroll_offset_y)
this_screen.scroll_offset_y = SCROLL_Y;
else
this_screen.scroll_offset_y = this_screen.max_scroll_offset_y;
}
else
{
offset_x = this_screen.player_feet_x-this_screen.feet_x; // George's offset from the centre - the desired position for him
offset_y = this_screen.player_feet_y-this_screen.feet_y;
// prevent scrolling too far left/right/up/down
offset_x = offset_x < 0 ? 0 : ( (uint32)offset_x > this_screen.max_scroll_offset_x ? this_screen.max_scroll_offset_x : offset_x );
offset_y = offset_y < 0 ? 0 : ( (uint32)offset_y > this_screen.max_scroll_offset_y ? this_screen.max_scroll_offset_y : offset_y );
if (this_screen.scroll_flag==2) // first time on this screen - need absolute scroll immediately!
{
//Zdebug(42,"init scroll");
this_screen.scroll_offset_x = offset_x;
this_screen.scroll_offset_y = offset_y;
this_screen.scroll_flag=1;
}
else // catch up with required scroll offsets - speed depending on distance to catch up (dx and dy) & 'SCROLL_FRACTION' used
{ // but limit to certain number of pixels per cycle (MAX_SCROLL_DISTANCE)
dx = this_screen.scroll_offset_x - offset_x;
dy = this_screen.scroll_offset_y - offset_y;
if (dx < 0) // current scroll_offset_x is less than the required value
{
scroll_distance_x = (1+(-dx)/scroll_fraction); // => inc by (fraction of the differnce) NB. dx is -ve, so we subtract dx/SCROLL_FRACTION
this_screen.scroll_offset_x += scroll_distance_x < MAX_SCROLL_DISTANCE ? scroll_distance_x : MAX_SCROLL_DISTANCE;
}
else if (dx > 0) // current scroll_offset_x is greater than the required value
{
scroll_distance_x = (1+dx/scroll_fraction); // => dec by (fraction of the differnce)
this_screen.scroll_offset_x -= scroll_distance_x < MAX_SCROLL_DISTANCE ? scroll_distance_x : MAX_SCROLL_DISTANCE;
} // NB. I'm adding 1 to the result of dx/SCROLL_FRACTION, because it would otherwise
// not scroll at all when dx < SCROLL_FRACTION
if (dy < 0)
{
scroll_distance_y = (1+(-dy)/scroll_fraction);
this_screen.scroll_offset_y += scroll_distance_y < MAX_SCROLL_DISTANCE ? scroll_distance_y : MAX_SCROLL_DISTANCE;
}
else if (dy > 0)
{
scroll_distance_y = (1+dy/scroll_fraction);
this_screen.scroll_offset_y -= scroll_distance_y < MAX_SCROLL_DISTANCE ? scroll_distance_y : MAX_SCROLL_DISTANCE;
}
}
}
}
//------------------------------------------------------------------------------------
int32 FN_set_scroll_coordinate(int32 *params) //Tony25Sept96
{
// set the special scroll offset variables
// call when starting screens and to change the camera within screens
// call AFTER FN_init_background() to override the defaults
// called feet_x and feet_y to retain intelectual compatibility with Sword1 !
// feet_x & feet_y refer to the physical screen coords where the system will try to maintain George's feet
// param 0 feet_x value
// param 1 feet_y value
this_screen.feet_x = params[0];
this_screen.feet_y = params[1];
return(IR_CONT);
}
//------------------------------------------------------------------------------------
//------------------------------------------------------------------------------------
int32 FN_set_scroll_speed_normal(int32 *params) // James08aug97
{
scroll_fraction=16;
return(IR_CONT);
}
//------------------------------------------------------------------------------------
int32 FN_set_scroll_speed_slow(int32 *params) // James08aug97
{
scroll_fraction=32;
return(IR_CONT);
}
//------------------------------------------------------------------------------------
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